Method of manufacture of homogeneous compositions



' 3,070,436 METHOD on MANUFACTURE OF HOMOGENEOUS COMPOSITIONS Bernard lL-Triflleman, Fair Lawn, NJ., assignor to Curties-Wright Corporation, New York, N a corporation of Delaware t r v No Drawing. Filed Mar. 17, 1959, Ser. No. 799,855

11 Claims. (Cl. 75-05) The present invention relates to a method for manufacturing homogeneous compositions of several elements,

. and in particular to the production of homogeneous compositions of dispersions of a metal phase and oxides of finite size, in alloys, cermets and ceramics This is a con tinuation-in-part of my earlier filed application Serial No.

566,767, filed .February 21, l956, 'and entitled Method of Manufacture of Homogeneous Compositions, now Patent No. 2,893,859, issued July 7, 1959.

In accordance with my copending application, there was provided a method of preparing a homogeneous composition of several elements by starting with ahomogeneous solution of the several elements in a volatile sol vent. The term "solution included true solutions and colloidal suspensions. The solution of the severalelemerits was dried under conditions appropriate to drive ofi substantially all of the volatile solvent, without causing segregation of the several elements. I The drying action, which was characterized as quick-drying, formed a homogeneous molecular mixture of the several elements in solid form, which by further treatment, could be reduced to attain a molecular mixture in powdered form or a regulns alloy. Although the method of my copending application had numerous and substantial uses, at times the requirement is imposed that material, in theform of finite size particles, is to be uniformly dispersed in a matrix of 'an atomic mixture of the several elements of Illustrative of this requirement is the need to disperse uranium oxide unithe alloy, 'cermetor ceramic mixture.

formly in'stainlesssteel or other similar corrosion-resistant'metals' for use in nuclear reactors. Further, the

process of mycopending application can be used only in the production of alloy powders which can be produced from mixed oxides below the melting temperature of the desired alloy and below the temperature at which the one or more elements of the alloy would melt and separate from the remaining oxides. .As a practical matter, powders of alloys containing reactive metals such as aluminum, titanium and columbiumwere difficult, if not impossible, to manufacture by the disclosed process of said copending application. alloy or cermet of a particular composition, it was essential to practice the'entire process, including the several steps thereof. As a practical matter, it was not possible to prepare a standard or basic alloy of a prescribed com-' position; and then by the addition of materials thereto alter the composition to create a different, but somewhat related alloy. The practice of the complete process requires the initial set-up of the equipment for the manufacture of the particular alloy under consideration, followed by the task of cleaning out the equipment before beginning to process a different alloy. Consequently,,from

the cost standpoint, alloys or cermets which are not in homogeneous compositions which obviates one or more of the aforesaid difiiculties. I I

It is a further-object of the presentvinven'tion to provide a method for the manufacture of homogeneous compositions of a dispersion of a metal plase and oxides of Still further to arrive at an 3,070,436; Patented Dee,

finite size in alloys, cermetsand ceramics -wherein the metal phase is uniformly dispersed in-a matrix of such alloys, cermets or ceramics; 1

It is a still further. object-of the present invention to provide a method for the production of alloy metal powders andcerrnets from reactive metals, including without limitation aluminum, titanium and columbium'.

A still further object of the present invention is to provide a method which-facilitatesthe initial fabrication i of an alloy metal powder, with the facility to convert such alloy metal powderto a related alloy containing further metals and/or a diiferentcomposition. p

A further problem which may be presented in the production of true alloy powders is the difiiculty of working Q,

Frequently, i

quetting of such powders into parts and/or the rolling of such powders into strips of materials. Typical alloy powders which are not readily worked due to theirhard ness or britleness are Alnico V and Renet 21., further, very few fabricating plants are equipped to manufac ture powdered metal parts by pressing such powdered metals and heating the resulting green compact, twhich coupled with the difficulty in the first'instance .of making certain parts by this technique, points to the need for the facility to convert alloy powder into strip form. With the conversion of such: alloy powders into strips of material, new fields ofuse for-alloy metal powders be come available. Certain materials cannot be readily fabricated by conventional techniques. Specifically, some g of these materials are rather expensive to fabricate (e.g. thin gauge Inconel 'X). Others are rather difficult to fabricate (e.g. Renet 21) and still others are virtually impossible to fabricate (e.g. cermets and alloy and cermetdispersions).

Accordingly, it is a further object of the present invention to provide an improved method for manufacturing alloy powders which have characteristics making it readily possible to fabricate such alloy powders, and advantageously roll certain'of these alloy powders into strip form. Specifically, it is within the scope of" this .invention to fabricate by powder metallurgy techniques materials which heretofore were difiicult, virtually. impossible and extremely expensive to fabricate.

In accordance with illustrative method aspects of the present invention, there is provided a method for the manufacture of homogeneous compositions of dispersions of a metal phase and oxides of finite size in alloys, cermets and ceramics which comprises the steps of preparing a homogeneous solution'of the several elements in the composition in a volatile solvent including constituents selected from the group consisting of nitric acid, sulphuric acid, ammoniaand water. The term solution in they instant application is iritended to include dispersions of finite particles. The phase to be dispersed is added in solid form to the solution and the resultant solution dispersion is blended until a uniform system is achieved."

The solution-dispersion is then subjected to quick drying d to drive oil a substantial amount of the volatile solvent under conditions selected to preclude segregation of the several elements and to assure the formation of a homogeneous molecular mixture of the several elements surrounding a homogeneous dispersion of the phase in solid form.

phase of finite size, such as an oxide. Examples of the i alloy metal powders which can be made include, without with a dispersed phase of thorium oxide.

" several elements in solid form.

treated toflobtain-areduced powder and the reduced -seri tied temperature in accordance with the torer'nove the remainder of the volatiles.

. limitation, stainless steel with uranium oxide as a dis- 'persed phase and monel-five-pereent aluminum oxide f In accordance with further method aspects of the pres- ]ent: invention, it is .possible to initially manufacture a ,homogeneous composition of a basic alloy metal and/or {ceramic by preparing a homogeneous solution of the frequisite composition in .a volatile solvent, including con- Istituents selected from .the group consisting of nitric acid, sulphuric :acid, ammonia and water, with the solution being subjected to quick drying under conditions to preelude segregationv of the several elements and to assure the formation of a homogeneous molecular mixture of the The mixture is then powder may be heated in the presence of a powdered alloy of unreducible and/or additional metals to effect further alloying to obtain a desired end composition. As an example of this, a 304 stainless steel may be made according to my process, and by the addition of terrocontrolled atmosphere for 'apreseribed time and at a pre- I materials under consideration.

' j' The .following examples will illustrate the manner in which the present invention-may be employed to practice .the'rnanufacture of homogeneous compositionsfbut it is tobe -expressly understood'that the invention is not limited these illustrative examples:

- EXAMPLE I 90% 3 04 Stai'nless Steel-% Aluminum Oxide (Con- -tinuor ts Phase), 90% by weight; Zirconium Dioxide,

weight .11 20.15 mic r onraverage size (Dispersed Phase), 10% I 63parts iron, s ans nickel, and 15.3 wt.

. Alton).

dissolved in excess nitric acid; 36 parts chromic acid werjefdissolved in a little water and the solutions were mixed and concentrated to a boiling point of 118 C. To theconcentrated solution was added 11 parts of zirconium d1 eof a'size of .2025, microns. The solution-dispers io was mixed in a blender until a uniform system was achieved.

(2') nae resulting, solution-dispersion was fed dropwise,

while being "stirred, onto a hot metal surface maintained 00 C. and left there for 30 seconds whereupon a subsienna: amount of the volatile solvent distilled. A solid homogeneous product resulted. v

' product was heated at 800' C. for minutes homogeneous product was ground in a ham- I mill untilfthe particles all passed a screen of 100 The powder was then reduced in a tube furnace flit r a hydrogen atmosphere at 1000 C. for 60 minutes. iotthe'oxygen was removed from the iron, nickel, andchromium oxides.

- The resulting powder was deagglomerated andmixedwith a stoichiometric amount of lampblack to reeremaining oxides of chromium-iron-nicltel to carbpnmonoxide. H

' '!(7') powder was then further reduced at 1150 C. for. 30-minutes' under a low flow of hydrogen.

.18 The productwas deagglomerated and theresulting powder was nbn-magnetiq-corrosion resistant to nitric This strip. was sintered at.9'00 C.':for one :hour hydrogen and was then rolled down to 0.020 inch. The

' heated at 750 C. in a rotary kiln for 30 minutesu'nder The resulting powder had sintered slightly and was easily broken up :to a size fincl'; powder, when tested as the 4600 steel powder, showed atensile acid, sponge-like in'strueture, and contained no carbon. This powder was easily pressed under normal powder metallurgy pressures and showed good strength after sintering. The powders wereable to be easily rolled into strip form and exhibited after sintering both the formability of metals and the heat stability of ceramics EXAMPLE 11 p Alnico V Powder and Strip j (l) Alnico V mixingalloy powder of a size liner that! 100v mesh and of a composition of 28.6% Co, 3.6% Cu, 51.2% Fe and 16.5% Ni'was made according to the general procedure detailed in my copending application.

336 parts of this powder was-mixed with '64 parts-of a 50% Al, 50% Fe powder of a'size finer than 325 mesh. 7

The powder was heated ina rotary kiln at 875" C. forv 30 minutes under a hydrogen atmosphere. The powder! had sintered slightly but were easily 'bro'ltenalp to finer 7 than 100 mesh. The powder, a partially alloyed V material, had a composition of 8% Al, 24%, Co, 3%

. Cu, 51% Fe, and 14% Ni. This powder was able to be pressed and sintered, and the :sinterings showed higher density and better sintered properties than a similar part made from primary powders. Further, the powder was fed-to a rolling mill with horizontal. rolls and a green s't'rip obtained which was of the order of 0.035 inch thick.

strip was' then resintered at 900 C. for :onel'hour rolled to 0.010 inch. v For comparison purposes, an alloyed powder was ,rnade .by grinding cast Alnico and it was attempted .to pres'sfgand roll bond this .Alnico" powder. In both operations, the:

' powders could not be compacted to the desired EXAMPLE III p SteeIPawdenAlSl 4650 An AISI 4600 steelpowder of a'sizei fi.... a....;-. 1 mmesh and of acomposition' of 97.75% Fe, 2.0% "Ni' ahtl 0.25% M0 was made according to "the general .prooedure' detailed in my copendingapplication. Thispowde'n'wh'en tested by being pressed .at 40 tons per square 'ineli fol lowed by sintering at-ll50 C. for one hour under hydr gen, was found to have a tensile strength of 3t0,000 p.s; andan elongation of 15%. 9.9.5 parts of this 4600 steel powder was then mixed with 0.55 part lampblaelt a 1 hydrogen atmosphere.

than 100 mesh. This powder, a'4650 steel of 79,000 p.s.i. and an elongation of 2.9%.

EXAMPLE rv' Renet #21, Powder mash: p A Renet 21 mixing alloy powder of a size finer mesh and of a composition of 12.4% C0, 20.9% 11.0% Mo, and 55.7% Ni was made according m ne;

general procedure detailed in my eopending application 91 parts of this alloy was mixed with 6 parts of a 50% Ni, 50% Ti powder, 3 parts .ofa 50% Ni, 50% A1 powder" and 0.13 part of lampblack, the latter powders all being finer than 325 mesh. The. powders were heated in a tube furnace at 900 C. under a hydrogen atmosphere for one hour. The powders were sintered slightly, but were'easilyi' broken up to a size finer than 100 mesh. The powder, a;

partially alloyed Renet 21, had a composition of 1.5%-1Al; f

0.12% C, 11.3% C0, 19% Cr, 10% balance Ni.

This powder was able to be easily pressed and .sinteied aj and the green bar showed excellent handling strength and the sintered bar showed excellent tensile strength. Further, this powder was fed-to a rolling mill, with .horizdittalai' .rolls and a green strip of the order of 0.034 inch for onejhour under a hydrogen atmosphere.

phase of finite size, and strip of material.

with excellent handling strength was obtained; This strip was sintered at 1100" C.v for one hour under a low flow of hydrogenand was then rolledin a two-high vertical mill to 0.019 inch thick. The resulting strip was heated at 1200 C. for one hour under a low hydrogen flow and then rerolled to 0.010 inch in a two-high vertical mill. The resulting'strip was found to have excellent strength.

EXAMPLE V j 90% Stainless Steel-10% Aluminum Oxide. Cermet in Strip Form A 90% 304 stainless steel-10% A1 cermet powder of a size finer than 100 mesh was made according to the general procedure detailed in my copending application.

This powder was fed to a rolling mill with horizontal rolls and a green strip 0.020 inch thick and with good handling strength obtained This strip was sintered at 1200 C. The strip was then rolled down to 0.010 inch and showed good room temperature strength coupled with excellent high temperature strength.

What I claim is: v

1. A method for manufacturing homogeneous compositions of several elements including at least one metal and a dispersed oxide phase of finite particle size in alloys, cermets' and ceramics comprising the steps of preparing a homogeneous solution-of the several elements, in the composition in a volatile solvent including constituents selected-from the group consisting of nitric acid, sulfuric acid, ammonia, and water, adding said oxide phase to be dispersed in solid form to said solution and blending the resultant solution-dispersion, subjecting said solution-dispersion to quick drying to drive off a substantial amount of said volatilesolvent under'conditions selected to prec'lude segregation of said several elements and to assure the formation of a homogeneous molecular mixture of said several elements surrounding a homogeneous dispersion of said oxide phase in solid form, reducing said mixture to obtain a powder with a homogeneously dispersed rolling said powder to obtain a The method according to claim 1 including the further step of heating said strip under a controlled atmosphere for a time period in'the range of to 120 minutes and at a temperature in the range of 500 C. to 1500 C.

3. In a method for manufacturing homogeneous compositions of alioy metals and cermets, the steps of preparing a homogeneous solution of the several elements in the composition in a volatile solvent including constituents selected from the group consisting of nitric acid, sulfuric acid, ammonia and water, subjecting said solution to quick drying to driveiotf a substantial amount of said volatile solvent under conditions selected to preclude segregation of said several elements and to assure the formation of a homogeneous molecular mixture of said several elements in solid form, treating said molecular mixture to obtain a powde'rand reducing said .powder, and heating said powder with another alloy powder of a finer'size under a controlled atmosphere for a time period in the range of 10 to 120 minutes and at a temperature in the range of 500 C. to 500 C.

'4. In a method for manufacturing homogeneous compositionsof alloy metals and cermets, the steps of preparing a homogeneous solution of the several elements in thecomposition in a volatile solvent including constituents selected from the group consisting of nitric acid, sulfuric acid, ammonia and water, subjecting said solution to quick drying to drive off a substantial amount of said volatile solvent under conditions selected to preclude segregation of said several elements and to assure the formation of a homogeneous molecular mixture of said several elements .in solid form, further heating said molecular mixture to drive ofl any residue of said volatile solvent, treating said molecular mixture to obtain a powder and reducing said powder, heating said powder with another alloy powder of a finer size under'acontrolled at mosphere for a time period in the range "of i0 to'f-120 minutes and ata temperature in-the range of;-500-C.'to 1500" C., and rolling the resultantpowder to 'obtain a strip of material. v. 5. In the method according to' claim-4, the furtherstep of heatingsaid stripunder a controlled atmospherefor a a time period in the rangeof 10 to minutes and a I I temperature in the range of 500 C. to 1500 C.

6. In a method for manufacturing 'homogeneou's com 3 positions of alloy metals and cermets, the-steps, of preparing a homogeneous solution of the severalelenients in the composition in'a volatile solvent including constituents selected fromthe group consisting of nitric acid, sulfuric acid, ammonia and water, subjecting said'solution of heating said strip under a controlled atmopshere for a a time period in the range of 10 to 120 minutes and atatemperature in the range of 500 C. to 1500" C.

8. A method for manufacturing homogeneousmcom positions of alloys, cermets, and ceramics having dispersed therein oxide of finite size, comprising the steps of preparing a homogeneous solution .of the several elements in;

the composition in a volatile solvent including at .least one constituent selected from the group consisting -of nitric acid, sulfuric acid, ammonia, .and water; addin wto said solution an oxide of finite particle size and insoluble in said solvent and blending the resultant solution-dispersion; and subjecting said solution-dispersion to quick drying to drive off .a substantial amount of said volatile solvent under conditions selected to preclude segregation of said several elements and to assure the formation, ofa homogeneous molecular mixture of said several elements homogeneously surrounding a sized oxide particles. a

9. A method for manufacturing homogeneousgcompositions of alloys, cermets, and ceramics having ,dis-. persed therein oxide of finite size, comprising the steps of preparing a homogeneous solution of the several elementsin the composition in a volatile solvent including at least one constituent selected from the group consisting ofnitric acid, sulfuric acid, ammonia, and water; adding toj said solution an oxide of finite particlesize and insoluble in f said solvent and blending the resultant solution-dispersion; and subjecting said solution-dispersion to quick drying to drive off a substantial amount of said volatile solvent under conditions selected to preclude segragation of said several elements and to assure the formation of a homogeneously surrounding a dispersion of said finites'ized.

oxide particles, and reducing said mixture to obtaina powder with a homogeneously dispersed phase 'of'finitc:

size.

positions of' alloys, cermets, and ceramics havin'g dis' parsed therein oxide of finite size, comprising the steps: of preparing a homogeneous solution of the several ele-' ments in the composition in a volatile solvent including quick drying to drive off a substantial amount of said volatile solvent under conditions selected to preclude segregation of said several elements 5113 to assure' lth e formation of a homogeneous molecular mixture dispersion of saidfinite;

10. A method for manufacturing homogeneouscom i Y several elements homogeneously surrounding a dispersion "of saidfinite sized oxide particles, reducing said mixture .to'ohtain'a powder with a homogeneously dispersed phase of finite size, and then heating said powder with another alloy powder of a ,finer size under a controlled atmosphere fora time period in the'range of 10 to 120 minutes and a temperature in the range of 500 C. to 1500? C.

acid, ammonia and water, adding said-oxide phase to be dispersed in solid form tosaid solution, and blending the resultant solution-dispersion, subjecting said solution-dis- 1 persion to quick drying to driveotf a substantial amount of said volatile solvent under conditions selected to preclude segregation of said several elements and to assure 8 the-formation of a homogeneous molecular 'mixtu'te of said severalelements surrounding ahor'nogeneous 'dispersion of said oxide phase insolid form'gxreducing' said mixture to obtain apowder with a homogeneously dispersed phase of finite size, andthen heating said'po'wder with another alloy powder .of a finer size under a .con-' trolled atmosphere for a time period in the, range of 10 to 120 minutes and a temperature in the range of $00 to 1500' c. I

References Cited in the file of this patent UNITED STATES PATENTS 1,319,589 Jones Oct-21, 1919 2,406,172 Smithells Aug. 20,1946

2;893,859 Triflleman' July 1,1959

' FOREIGN PATENTS 784,153 Great Britain Oct. 2, 1951 

1. A METHOD FOR MANUFACTURING HOMOGENOUS COMPOSITIONS OF SEVERAL ELEMENTS INCLUDING AT LEAST ONE METAL AND A DISPERSED OXIDE PHASE OF FINITE PARTICULES SIZE IN ALLOYS, CERMENTS AND CERAMICS COMPRISING THE STEPS OF PREPARING A HOMOGENEOUS SOLUSTION OF THE SEVERAL ELEMENTS IN THE COMPOSITION IN A VOLATILE SOLVENT INCLUDING CONSTITUENTS SELECTED FROM THE GROUP CONSISTING OF NITRIC ACID, SULFURIC ACID, AMMONIA, AND WATER, ADDING SAID OXIDE PHASE TO BE DISPERSED IN SOLID FORM TO SAID SOLSUTION AND BLENDING THE RESULTANT SOLUTION-DISPERSION, SUBJECTING SAID SOLUTION-DISPERSION TO QUICK DRYING TO DRIVE OF F A SUBSTANTIAL AMOUNT OF SAID VOLATILE SOLVENT UNDER CONDICTIONS SELECTED TO PRECLUDE SEGREGATION OF SAID SEVERAL ELEMENTS AND TO ASSURE THE FORMATION OF A HOMOGENEOUS MOLECULAR MIXTURE OF SAID SEVERAL ELEMENTS SURROUNDING A HOMOGENOUS DISPERSION OF SAID OXIDE PHASE IN SOLID FORM, REDUCING SAID MIXTURE TO OBTAIN A POWDER WITH A HOMOGENEOUSLY DISPERSED PHASE OF FINITE SIZE, AND ROOLING SAID POWDER TO ONTAIN A STRIP OF MATERIAL. 